Hi Bharata,
Bharata B Rao <bhar...@linux.ibm.com> writes:
> Make GTSE an MMU feature and enable it by default for radix.
> However for guest, conditionally enable it if hypervisor supports
> it via OV5 vector. Let prom_init ask for radix GTSE only if the
> support exists.
>
> Having GTSE as an MMU feature will make it easy to enable radix
> without GTSE. Currently radix assumes GTSE is enabled by default.
>
> Signed-off-by: Bharata B Rao <bhar...@linux.ibm.com>
> Reviewed-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>
> ---
> arch/powerpc/include/asm/mmu.h | 4 ++++
> arch/powerpc/kernel/dt_cpu_ftrs.c | 1 +
> arch/powerpc/kernel/prom_init.c | 13 ++++++++-----
> arch/powerpc/mm/init_64.c | 5 ++++-
> 4 files changed, 17 insertions(+), 6 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h
> index f4ac25d4df05..884d51995934 100644
> --- a/arch/powerpc/include/asm/mmu.h
> +++ b/arch/powerpc/include/asm/mmu.h
> @@ -28,6 +28,9 @@
> * Individual features below.
> */
>
> +/* Guest Translation Shootdown Enable */
> +#define MMU_FTR_GTSE ASM_CONST(0x00001000)
> +
> /*
> * Support for 68 bit VA space. We added that from ISA 2.05
> */
> @@ -173,6 +176,7 @@ enum {
> #endif
> #ifdef CONFIG_PPC_RADIX_MMU
> MMU_FTR_TYPE_RADIX |
> + MMU_FTR_GTSE |
> #ifdef CONFIG_PPC_KUAP
> MMU_FTR_RADIX_KUAP |
> #endif /* CONFIG_PPC_KUAP */
> diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c
> b/arch/powerpc/kernel/dt_cpu_ftrs.c
> index a0edeb391e3e..ac650c233cd9 100644
> --- a/arch/powerpc/kernel/dt_cpu_ftrs.c
> +++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
> @@ -336,6 +336,7 @@ static int __init feat_enable_mmu_radix(struct
> dt_cpu_feature *f)
> #ifdef CONFIG_PPC_RADIX_MMU
> cur_cpu_spec->mmu_features |= MMU_FTR_TYPE_RADIX;
> cur_cpu_spec->mmu_features |= MMU_FTRS_HASH_BASE;
> + cur_cpu_spec->mmu_features |= MMU_FTR_GTSE;
> cur_cpu_spec->cpu_user_features |= PPC_FEATURE_HAS_MMU;
>
> return 1;
> diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
> index 90c604d00b7d..cbc605cfdec0 100644
> --- a/arch/powerpc/kernel/prom_init.c
> +++ b/arch/powerpc/kernel/prom_init.c
> @@ -1336,12 +1336,15 @@ static void __init prom_check_platform_support(void)
> }
> }
>
> - if (supported.radix_mmu && supported.radix_gtse &&
> - IS_ENABLED(CONFIG_PPC_RADIX_MMU)) {
> - /* Radix preferred - but we require GTSE for now */
> - prom_debug("Asking for radix with GTSE\n");
> + if (supported.radix_mmu && IS_ENABLED(CONFIG_PPC_RADIX_MMU)) {
> + /* Radix preferred - Check if GTSE is also supported */
> + prom_debug("Asking for radix\n");
> ibm_architecture_vec.vec5.mmu = OV5_FEAT(OV5_MMU_RADIX);
> - ibm_architecture_vec.vec5.radix_ext = OV5_FEAT(OV5_RADIX_GTSE);
> + if (supported.radix_gtse)
> + ibm_architecture_vec.vec5.radix_ext =
> + OV5_FEAT(OV5_RADIX_GTSE);
> + else
> + prom_debug("Radix GTSE isn't supported\n");
> } else if (supported.hash_mmu) {
> /* Default to hash mmu (if we can) */
> prom_debug("Asking for hash\n");
> diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
> index bc73abf0bc25..152aa0200cef 100644
> --- a/arch/powerpc/mm/init_64.c
> +++ b/arch/powerpc/mm/init_64.c
> @@ -407,12 +407,15 @@ static void __init early_check_vec5(void)
> if (!(vec5[OV5_INDX(OV5_RADIX_GTSE)] &
> OV5_FEAT(OV5_RADIX_GTSE))) {
> pr_warn("WARNING: Hypervisor doesn't support RADIX with
> GTSE\n");
> - }
> + cur_cpu_spec->mmu_features &= ~MMU_FTR_GTSE;
> + } else
> + cur_cpu_spec->mmu_features |= MMU_FTR_GTSE;
The GTSE flag is set by default in feat_enable_mmu_radix(), should it
be set again here?
Thanks,
Santosh
> /* Do radix anyway - the hypervisor said we had to */
> cur_cpu_spec->mmu_features |= MMU_FTR_TYPE_RADIX;
> } else if (mmu_supported == OV5_FEAT(OV5_MMU_HASH)) {
> /* Hypervisor only supports hash - disable radix */
> cur_cpu_spec->mmu_features &= ~MMU_FTR_TYPE_RADIX;
> + cur_cpu_spec->mmu_features &= ~MMU_FTR_GTSE;
> }
> }
>
> --
> 2.21.3
